1. Field of the Invention
The present invention relates to an ultrasonic therapeutic apparatus in which the distal end of a probe is subjected to ultrasonic vibration, thereby crushing or emulsifying organic tissues, and operations for cooling water supply and suction are performed.
2. Description of the Related Art
A typical ultrasonic therapeutic apparatus comprises a hand piece having an ultrasonic vibrator therein, a probe connected to the hand piece, and a drive source unit for driving the vibrator. Since the probe is heated by internal strain which is attributable to ultrasonic vibration, the ultrasonic therapeutic apparatus is furnished with a water supply mechanism which supplies the probe with cooling water, such as a physiological saline solution, thereby cooling the probe and washing the operation field. The apparatus is further provided with a suction mechanism for removing tissue pieces or crushed pieces, along with the supplied cooling water, by suction.
The ultrasonic therapeutic apparatus with this construction can crush organic tissues and successively remove crushed tissue pieces by suction, by subjecting the distal end of the probe to ultrasonic vibration. This apparatus is characterized, however, in that it never crushes elastic tissues, such as vascular tissues, nervous tissues, etc., so that it is suited for resection of the liver and cerebral surgery.
Among specific examples of the ultrasonic therapeutic apparatus of this type, there is one which is provided with a mechanism capable of freely adjusting the quantity of cooling water supply to the probe. Another example is proposed in Jpn. Pat. Appln. Publication No. 3-318867 (Jpn. Pat. Appln. KOKAI Publication No. 5-168697). In this case, the apparatus is driven after preset values for an ultrasonic output and a feedwater output for cooling water are set by reading preset values stored in an internal memory for the preceding cycle of operation.
According to the former ultrasonic therapeutic apparatus in which the quantity of cooling water supply can be freely set, an operator must take the greatest care not to carry out a surgical operation with the cooling water supply at its minimum value or zero. If a preset value for the cooling water supply is changed in the ultrasonic therapeutic apparatus of this type, the probe may not be able to be fully cooled because the quantity of cooling water supply is too small for the ultrasonic output, or the operation field cannot be washed clean enough to secure a distinct field of view. In such a case, the use of the apparatus must be suspended.
The latter ultrasonic therapeutic apparatus proposed in Jpn. Pat. Appln. Publication No. 3-318867 involves the same problem of the former one unless the preset feedwater output value for the preceding operation cycle, invoked from the memory during the operation of the apparatus, is appropriate to the ultrasonic output.
Thus, in the ultrasonic therapeutic apparatus, the water supply to the probe is an essential factor, and the probe should never fail to be properly supplied with water before ultrasonic oscillation. If the water supply is stopped during the ultrasonic oscillation, moreover, the ultrasonic oscillation must be suspended in order to avoid the aforementioned awkward situation.
Depending on the application, the conventional ultrasonic therapeutic apparatus requires the provision of hand pieces and probes with different shapes, sizes, outputs, etc. For example, there are many types of hand pieces, including a bent type for cerebral surgery, standard type for general surgical operation, high-power type for orthopedic or endoscopic treatment, etc. Also, the probes are varied in distal end shape and length, and some of them have a bent portion. It is poor economy, however, to provide many ultrasonic therapeutic apparatuses for individual applications, and storing them is a hard task.
To cope with this, a novel system is proposed in Jpn. Pat. Appln. Publication No. 2-283322 (Jpn. Pat. Appln. KOKAI Publication No. 4-158856. According to this system, a plurality of combinations of hand pieces and probes can be freely selected according to the application, the selected combination is detected or discriminated, and drive conditions are set in accordance with the combination. To attain this, each hand piece is discriminated by identification means attached to its connector, and the type of the probe is identified by detecting impedance by means of a control section in a drive unit. This system eliminates the aforesaid conventional drawback that an ultrasonic therapeutic apparatus must be provided for each application, and has an advantage in being able to be driven by means of a common drive unit despite the change of the combination of the hand piece and the probe.
Also in this system, the water supply to the probe is essential in washing the operation field or preventing the probe from being heated or damaged. It is necessary, therefore, to detect or discriminate the types of the hand piece and the probe and secure the optimum drive conditions for the combination of the two elements, and also, to set optimum conditions for a water supply pump, thereby adjusting the quantity of water supply to an optimum value corresponding to the ultrasonic oscillation output. Naturally, the drive conditions, including the oscillation output of ultrasonic vibration, in particular, are often expected to be changed depending on the varied tissues, despite the use of the same hand piece and probe. In some surgical operation, the tissues to be treated may cover various regions including adipose tissue, parenchyma of the liver, ambient regions of lymph nodes and blood vessels, and the like. In this case, an optimum oscillation output must be set for each of the tissues.
According to the system proposed in Jpn. Pat. Appln. Publication No. 2-283322, however, preset values for the oscillation output and the quantity of water supply must be changed independently by manual operation. If the quantity of water supply is too small for the oscillation output, therefore, the probe may possibly be heated to be damaged or cause a patient or operator to suffer a burn. If the water supply is too much for the oscillation output, on the other hand, plenty of water flows out from the distal end of the probe into the operation field. As a result, the operation field cannot be clear enough to advance the operation, and the feedwater is inevitably wasted.